You have the freedom to be entirely focused on academics in the US, participating in research etc. But you also have the freedom to live off your loans without any serious focus on academics, treating college like a vacation more than anything else. For the "students" who are tempted by the latter option, college is a waste.
The European commission already tried to swap all systems for a loan based one twice.
Which "European model" are you talking about ? If there is any of the models worthy of being called "European model", surely it'd be the commission's model, which would be the US model (with the state going after students who fail to pay, not sure about bankruptcy cases).
The USA is like the EU, where the various states vary as much if not more than the countries in the EU. The USA is far more racially varied than individual EU countries. The USA has used two big main policy tools to right wrongs of the past: home ownership and education. This has led to terrible policies, like the crazy mortgage crisis and student loan act, that means you can never get out of the debt through bankruptcy, which is morally extremely questionable.
When you have debt that can never liquidate, things get a little crazy, and a lot of the US college craziness is as a result of too much guaranteed money.
In the US, living on campus is the norm, a vast array of amenities and services are offered to students, and University bureaucracies are huge and growing by the year.
Contrast this with Europe, where many Universities are simpler affairs with students living at home, commuting to classes (which have higher student to professor ratios) at Universities without student centers, gyms, etc.
It's not that the US through sheer stupidity is missing out on some easy fix for college costs, the issue is simply that in the US Universities offer more than in Europe. This is in keeping with our overall culture.